Hammering tool



y 28, 1 'E. H. w WEIBULL 1,816,104

HAMMERING TOOL Filed Jan. 14, 1928 2 Sheets-Sheet 1 g /2 If July 28, 1931.

E. H. w. WEIBULL 1,816,104

HAMMERING TOOL Filed Jan. 14, 1 928 2 Sheets-Sheet 2 & QM s b e D s B E IN VEN TOR.

ATTORNEYS.

- Patented Jul 28,1931

UNITED STATES PATENT OFFICE ERNST HJ'ALMAIB WALODDI 'wEiIBULL, OI SAL'ISJ'OBADEN, SWEDEN, ABBIGNOB '10 AITIEBOLAGE'I' NOBDISKA AHATUBI'ABA, 0] STOOKHOLI, SW11)", A

I man courm v Application fled January 14, 1828, Serial No. 248,803, and in Sweden Rovember 28, 10111.

The present invention relates to striking or hammering tools which comprise'a rotating and reciprocating striking part and a non-striking guidin part cooperating with l the former part an which may or may not I rotate, the striking part coacting with a suitable anvil.

In such tools it is already known how to effeet, at the backward movement of the striking or hammering part, a storing of the whole or a part of the energy necessary for the forward movement (the power stroke) of the said part. Springs are commonlyused for this urpose, and it has also been proposed 15 to e ect the storage of energy by compression or rarefaction by the hammering body of the air located in front of or behind the hammering body.

Both these arrangements present certain 20 disadvantages in practice which are not found in the arrangement according to the invention, the tool according thereto being characterized by the provision of centrifugally governed bodies adapted during the backward movement of the striking part from the anvil to be displaced in opposition to the action of centrifugal force by guiding faces, the disposition of said guiding faces being such that, after the end of the backward movement, the striking part is urged towards the anvil through the intermediary of the xfaentrifugal bodies co-operating with said aces.

Other features characteristic of the invention will be described later in connection with the embodiments of the invention shown in the annexed drawings. The tool to which the invention has been applied by way of exampie is of the kind in which the backward movement of the striking or hammering body is effected by co-operation between one or more oblique or curved faces or the like, arranged on the striking body or the anvil, i. e. a tool constructed in accordance with the arrangement disclosed in patent specification No. 282,641.

Fig. 1 illustrates one embodiment, and Fig. la -a second embodiment of a tool according to the invention, in diagrammatic longitudinal section. Fig. 2 shows the rear part of another working position of the parts of the first embodiment.

Figs. 3, 4 and 5 show other embodiments of a tool according to the invention, in diagrammatic longitudinal sections. Figs. 6 and 7 show a further embodiment, in longitudinal section and in cross-section, alongFthe hne VIIVII Fig. 6 respectively, and 1g. 8 finally illustrates a seventh em-' bodiment, likewise in longitudinal section. F gs. 9 and 10 illustrate two power-diagrams. Fig. 11 is a longitudinal section of a complete 901 showing one embodiment of the invenion.

In all of these' figures, 1 is the striking part, 2 the guiding part, 3 the anvil and 4 and 5 the obli ue faces arranged on the striking part 1 an the anvil 3 and adapted toreturn the striking part after the power stroke.

Referring to the embodiment according to 1, the rear part 6 of the part 1 is prov1 ed with radial grooves 7, in which balls 8 are arranged to move. The guiding art 2 18 adapted to rotate in a frame 9 and is driven by an electric motor or the like. The guiding part 2 and the striking part 1 are keyed to each other by means of ton es and grooves 10, 11 in such a way that the striking part is forced to partake in the rotation of the guiding part, although it may, at the same time, perform a reciprocating movement relatively thereto. The groove 11 may be straight, or curved, or spiral-shaped in order to allow a shocklcss run of the striking body in the guiding part. The rear part of the guiding shell 2 is provided with inclined guiding faces 12 ada ted to force the balls 8 toward the center 0 rotation on the recoil of the striking member.

Referring to the embodiment according to Fig. 1a, the balls 8 replace the tongue 10, as they run in a groove 13 arranged in the guiding part, said groove also having the same purpose as the guiding face 12.

The arrangement works in the following 3n the part 1 strikin against the anvil 3 the energy of this stro e is transmitted to the anvil and the tool fixed therein, for instance a borer, chisel, riveting tool or the striking body is su 'jected, by the co-opera:

tion of the oblique faces 4 and and the 5 rapid rotation of the striking body, to a power component having a backward direction and returning the striking body. During backward or recoil movement of the striking body, the balls 8 are moved inwardly by the faces 12 and, due to the effect of centrifugal force, the balls oppose and eventually arrest the recoil movement of the str1k ing body. Following the arrest of the recoll movement of the striking body, the balls 8 rapidly revolving with the guide part 2. and striking. body bear on the inclined guiding faces 12 and due to centrifugal force they produce the following striking movement of the striking body.

In the embodiments shown in Figs. 1 and 1a the guiding faces 12, 13 merge into a cylindrical face owing to which, if the recoil movement of the striking body is so large that the balls reach this cylindrical face, said balls no longer tend to effect the anal movement of the striking body toward .the anvil.

-However,' axial movement of the striking body, under this circumstance, may be initiated by so disposing the tool that the striking body is caused to fall by gravity to a point where the balls 8 engage the inclined faces 12.

Referring to the embodiment shown in Fig. 3, the face 12, forwardly merges into an oblique or curved face 16 inclined in an opposite direction. 'From the above it will clearly appear that a face 16 arranged in this manner will produce a power component, acting upon the striking or hammering body in a direction opposite to, but parallel with the striking movement and will thus have a braking action upon it, if the striking body should get the opportunity of advancing so far that the balls run upon said oblique face 16. This arrangement is adapted to be used when the striking tool runs idle and thus protect the striking tool from being crushed.

The embodiment according to Fig. 4 shows a second shape of the guiding face 12, 16. In this case there is also a cylindrical guiding face 15 at the rear end and between this face 15 and the guiding face 12 there is an oblique guiding face 17 which prevents the balls 8.

, Fig. 5 shows another embodiment of the sup ort used for the centrifugal bodies 8; .these bodies, which may consist of balls, rollers or the like, are arranged to rotate in the ends of projections 19 or the like mounted so as to turnon the striking body 1.-

The arrangement is otherwise analogous to the embodiment according to Fig. 3, although the 'obligue faces'lfl, formed in a some- I what di erent manner.

Inthe embodiment according to Figs. 6 and 7 the obli ue faces 12 have, as shown, a considerable inclination so that the balls-8 may be given a large radial displacement, to enablea relatively large energy storage to be made witha small axial movement of the striking body.

-guiding part rotates.

Figs. 9 and 10 show a force and space dia gram illustrating the mutual relations of the amount of the centrifugal force and the above power component, the force of translation, in the embodiments according to Figs. 3 and 4. In the diagrams the forces are supposed to be indicated along the ordinates, distances along the abscissae. and the points a, a, b, d, e and C, A, B, D, E, respectively in Figs. 9 and 10 correspond to corresponding points in Figs. 3 and 4. The hatched areas'below the datum lines S represent the braking-energy absorbed bythe centrifugal bodies at the for ward motion of the striking body, passing that point at which the stroke shall normally be transmitted to the anvil and this energy should, if an effective protection is to be obtained, be as great as the striking energy transmitted previously to the striking body which energy is, in the diagram, indicated by the shaded area above the datum lines.

A complete tool is shown in Fig. 11 in which the electric motoris connected with and drives the guiding Dart 2, the latter being of the form shown in Fig. 1a. The motor is located in the frame 9, as will be understood.

Having now particularly described the nature of my invention and the manner of its operation, what I claim is:

1. In a striking or hammering tool, a strikmounted for rotary and reciprocating movement, means acting on the striking member in response to centrifugal force developed incident to-rotation thereof to effect striking movement of the striking member, and means acting in response to the impact of the striking member upon the anvil to efiect a recoil movement of the strildng member.

2. In a striking or hammering tool, a rotary drive shaft, an anvil, a striking body interposed in an axial direction between the shaft and anvil and adapted to engage the latter, means mounting said striking member for reciprocation, and .for imparting the ro tary movement of the drive shaft thereto, means coacting with said mounting means member.

ERNST I-UALMAR WALODDI WEIBULL. 

